The present invention relates to a demodulation process for a phase jump-modulated signals (or differential phase-modulated signals) permitting processing in time divided up over a plurality of transmission channels. The present invention also relates to a demodulator for performing this process.
Demodulators of the type referred to hereinbefore are used for decoding information (called hereinafter "symbols" and having groups of two or three binary elements called "dibits" or "tribits") contained in a differential phase-modulated signal, the modulation being at 1200 or 1600 Bauds corresponding to the coding of 2400 or 4800 binary elements per second. These demodulators must be able to work in time divided up over a plurality of channels, for example 32 channels in the case where telephone lines connected to MIC systems are used for transmitting this information.
The known demodulators do not carry out a correct demodulation in all cases of use and in particular when the signals received are subject to a high noise level and/or are greatly deformed, for example due to a high distortion caused by the transmission lines. Moreover, these known demodulators require the use of an automatic gain control device.